ocarina/lib/audio.cpp

/*
 * Copyright 2013 (c) Anna Schumaker.
 */
#include <audio.h>
#include <callback.h>
#include <deck.h>
#include <library.h>

#include <sstream>
#include <string.h>

static GstElement *ocarina_player;

static bool track_loaded = false;
static unsigned int cur_trackid = 0;

static bool o_pause_enabled = false;
static unsigned int o_pause_count = 0;
static bool o_should_pause = false;

static Playqueue o_recently_played(PQ_ENABLED);

static void parse_error(GstMessage *error)
{
	GError *err;
	gchar  *debug;

	gst_message_parse_error(error, &err, &debug);
	g_print("Error: %s\n", err->message);
	g_error_free(err);
	g_free(debug);
}

static void handle_pause_count()
{
	if (o_pause_enabled == false)
		return;
	else if (o_pause_count == 0) {
		o_should_pause = true;
		o_pause_enabled = false;
	} else
		o_pause_count--;
}

static gboolean on_message(GstBus *bus, GstMessage *message, gpointer data)
{
	switch (GST_MESSAGE_TYPE(message)) {
	case GST_MESSAGE_ERROR:
		parse_error(message);
		audio :: next();
		break;
	case GST_MESSAGE_EOS:
		handle_pause_count();
		audio :: next();
	default:
		break;
	}
	return TRUE;
}

static bool change_state(GstState state)
{
	GstStateChangeReturn ret;

	ret = gst_element_set_state(GST_ELEMENT(ocarina_player), state);
	switch (ret) {
	case GST_STATE_CHANGE_SUCCESS:
	case GST_STATE_CHANGE_ASYNC:
		return true;
	default:
		return false;
	}
}

static bool load_song(library :: Song &song)
{
	GstState state;
	gchar *escaped;
	std::string filepath = song.library->root_path + "/" + song.track->filepath;

	if (o_should_pause == true) {
		state = GST_STATE_PAUSED;
		o_should_pause = false;
	} else {
		gst_element_get_state(GST_ELEMENT(ocarina_player), &state,
					NULL, GST_CLOCK_TIME_NONE);
	}

	change_state(GST_STATE_NULL);
	escaped = gst_filename_to_uri(filepath.c_str(), NULL);
	g_object_set(G_OBJECT(ocarina_player), "uri", escaped, NULL);
	g_free(escaped);

	get_callbacks()->on_track_loaded(song);
	return change_state(state);
}

void audio :: init(int *argc, char ***argv)
{
	GstBus *bus;

	o_recently_played.set_flag(PQ_REPEAT);
	gst_init(argc, argv);

	ocarina_player = gst_element_factory_make("playbin", "ocarina_player");
	bus = gst_pipeline_get_bus(GST_PIPELINE(ocarina_player));

	gst_bus_add_watch(bus, on_message, NULL);
}

void audio :: quit()
{
	change_state(GST_STATE_NULL);
	gst_deinit();
}

void audio :: play()
{
	if (track_loaded == false)
		return;
	if (change_state(GST_STATE_PLAYING))
		get_callbacks()->on_play();
}

void audio :: pause()
{
	if (track_loaded == false)
		return;
	if (change_state(GST_STATE_PAUSED))
		get_callbacks()->on_pause();
}

void audio :: stop()
{
	pause();
	seek_to(0);
}

void audio :: seek_to(long pos)
{
	bool ret;
	if (track_loaded == false)
		return;
	ret = gst_element_seek_simple(GST_ELEMENT(ocarina_player),
					GST_FORMAT_TIME,
					GST_SEEK_FLAG_FLUSH,
					pos);
	if (!ret)
		throw -E_AUDIO;
}

void audio :: next()
{
	library :: Song song;
	unsigned int id;

	track_loaded = false;
	id = deck :: next();
	library :: lookup(id, &song);
	load_song(song);
	track_loaded = true;

	cur_trackid = id;
	o_recently_played.add_front(id);
	o_recently_played.reset_cur();
}

void audio :: previous()
{
	library :: Song song;
	unsigned int id;

	id = o_recently_played.next();
	if (id == cur_trackid)
		return;

	library :: lookup(id, &song);
	load_song(song);
	cur_trackid = id;
}

unsigned int audio :: current_trackid()
{
	if (track_loaded == false)
		throw -E_EXIST;
	return cur_trackid;
}

long audio :: position()
{
	long position;

	if (track_loaded == false)
		return 0;
	if (!gst_element_query_position(GST_ELEMENT(ocarina_player), GST_FORMAT_TIME, &position))
		return 0;
	return position;
}

std::string audio :: position_str()
{
	std::stringstream ss;
	long cur = position() / GST_SECOND;
	unsigned int minutes = cur / 60;
	unsigned int seconds = cur % 60;

	ss << minutes << ":";
	if (seconds < 10)
		ss << "0";
	ss << seconds;
	return ss.str();
}

long audio :: duration()
{
	long duration;

	if (track_loaded == false)
		return 0;
	if (!gst_element_query_duration(ocarina_player, GST_FORMAT_TIME, &duration))
		return 0;
	return duration;
}

void audio :: pause_after(bool enabled, unsigned int n)
{
	o_pause_enabled = enabled;
	o_pause_count = n;
}

bool audio :: pause_enabled()
{
	return o_pause_enabled;
}

unsigned int audio :: pause_count()
{
	return o_pause_count;
}